Acute lung injury (ALI) is a common, life-threatening complication among pediatric leukemia and lymphoma and hematopoietic stem cell transplant (HSCT) recipients. Although these children represent a relatively small and unique patient population, they account for the largest proportion of deaths of all pediatric diseases. The long-term goal of this project is to improve outcomes among these patients. Recently, the intratracheal administration of calfactant has resulted in decreased mortality among children with ALI including promising results among children with cancer and following HSCT. Consequently, the primary specific aim of this study is to assess the effect of calfactant on intensive care (PICU) survival among pediatric leukemia and lymphoma and HSCT patients with ALI. Secondary aims include assessment of the effect of calfactant on oxygenation and on the length of mechanical ventilation, PICU stay, and hospital stay. Calfactant therapy has been found to be of benefit in acute lung injury in the overall pediatric population by improving oxygenation and decreasing mortality. These findings, in conjunction with recent subgroup analysis in which calfactant therapy appeared to improve outcomes in immunocompromised children provide the rationale for assessing calfactant therapy in this patient population.